Marksmanship
ACE Marksmanship Guide
Here is where you will find the information for how to use the tools of a marksman.
extracted from wiki.ace-mod.net
A laser range finder is extremely handy. Just point at the target and lase it briefly. You'll get back your azimuth ( bearing to target in mils ), elevation difference and range to target. If working in two-man teams it's ideal for your spotter to carry one of these instead of binoculars. Just be sure to carry a spare battery or two.
While it may seem arcane, reading the map can get you a fair estimation of range. ArmA2 grid size depends how much you have zoomed in on it. The larger scale is marked in kilometers, the finer one in 100m increments. Count the grids both left-right and up-down between you and the target. Apply the rule of triangles c2 = a2 + b2 and add some fudge factor for any relative difference in position on the grids for you and that target. With a little practice you should be able to reliably estimate range within a 50m spread – good enough for many shots. Also note on the map the contour lines you and the target occupy. From that you can glean elevation info.
On many sniper scopes the reticle itself can serve as a range finder. The details vary but all use the same principal of stadiametrics. That is, if you know the size of the target and how big it appears you can calculate the range. The system used by Russian weapons like the SVD and T-90 tanks uses a horizontal line and a curved line above it calibrated to either human or tank-sized targets. You just slide the sight about until the target just barely touches both the horizontal and curved lines and then read off the number from the scale ( in hundreds of meters ). It's quick, but not super precise.
Other weapons often use the mil-dot system. Along the cross-hairs are a series of round or elliptical dots spaced at 1-mil increments. By using the shape and various standardized relationships between the various edges and centers you can estimate the image size to an accuracy of 0.1 mil. Then using the formula distance = target_size * 1000 / image_size, you'll get your range in meters. Soldiers typically are 1.7 - 1.8 meters tall.
If you have a wind meter called the Kestrel 4500 or you are lacking that particular tool, press the keybind SHIFT+K. This will either bring up the Kestrel interface or show you an arrow indicating the wind direction and approx. speed based on the color. If you do have the meter, click the calibrate button and take a reading. Crosswind speed is very important. You use that number in combination with the range card to determine the approx. windage offset needed.
Every weapon has a range where the center of the sight and range match exactly. This is called the Zero-Point. In ACE adjusting this point is done via the keybind SHIFT+V. This interface allows you to shift the weapon sights (usually the knobs on a scope). Here you can adjust the Range, Windage offset, and MOA (Minutes of Angle). Make sure you adjust for windage since ACE includes wind drift. You can also offset the sights to compensate for a running target.
extracted from wiki.ace-mod.net You should already know that stance has a big effect on how steady your aim is. Standing is the worse, crouching ok, and prone the best. Additionally in ACE2 you can rest your weapon on a wall or vehicle if close enough using SHIFT-SPACE combination. And if prone you can activate your weapon's bipod using the same sequence if it has one – you'll see a message telling you so if it does. Activating these mods limits the amount you can alter your aim so be close to on-target first. Moving too much or changing stance will deactivate these modes, just hit the key combo again once settled in.
BC or Ballistic Coefficient is how well an object resists reducing velocity as it passes through the air or other fluids. (Yes, air is a fluid) ArmA 2 and ACE ammunition models do not currently include individual BC values for different classes of ammunition. Mil or milliradian. There are 1/(2000*Pi) mils in a complete circle. NATO uses a 6400 mil scale, the WARSAW pact used the 6000 mil scale. Using the NATO scale, 1 mil subtends 1 meter at 1 kilometer. You can estimate the mils using your right hand.
MOA or Minutes of Angle or Arc indicates 1/60th of a degree. 1 MOA = 1 inch at 100 yards or approx. 2.91 centimeters at 100 meters. To convert from MOA to Mils use this formula: 1 mil = 3.438 MOA.